1. Field of the Invention
The present invention relates to a developer container which contains developing agent for developing an electrostatic latent image, a developer unit which develops an electrostatic latent image, and a process cartridge which comprises such a developer unit, as well as an image carrier of an electrostatic latent image, and which is removably set in an electrophotographic device.
2. Description of the Related Art
U.S. Pat. No. 4,981,218 discloses a developer container employing a sheet-like sealing member to seal a developer-discharging opening of the developer container body. Such a sealing member is adhered by heat-welding, etc., to an adhesion area surrounding the opening. When the developer container is to be used, the sealing member is peeled off from the adhesion area to clear the opening.
Since the sealing member must be adhered to the container body so as to be peeled off later, the above known art requires an accurate control of the adhesion strength therebetween. If the adhesion strength is rather weak, the sealing member may be easy for an operator to peel off, however, it is also more likely to peel off at an inopportune moment, e.g. during transportation, in which case a leakage of the developer may well result. Also when an operator peels off the sealing member, it sometimes tears leaving a piece thereof at the opening because of a scratch or a crack in the sealing member or damage thereof caused by the adhering process.
To solve such problems of the above known art, Japanese Pat. Laid-Open No. 59-13262 discloses art employing a sealing member which is easy to tear parallel to one specific straight line or which has a line with perforations, scoring, etc. to seal the above-mentioned opening. For use, a long strip portion is torn off from the sealing member to form a long opening in the sealing member.
In such art, however, there is a tendency for the strip portion being torn off to become narrower or wider as the tearing progresses. If the opening is formed with its width varying over the course of the tearing, the amount of developer supplied to the development chamber becomes uneven, i.e. it varies at different locations thereof.
U.S. Pat. No. 4,931,838 discloses art which solves such problems. In the art disclosed, a sealing member is provided with a tear tape adhered thereto, and, for use, the sealing member is torn to form an opening by pulling the tear tape.
However, the process of adhering the tear tape to the sealing member may add to production costs.